Temperature-responsive device



Nov. l1, 1930. L. J. .1. B. cHENEAu 1,781,630

TEMPERATURE RESPONSIVE DEVICE Filed June 27, 1927 7l Z 2 Ff l 50 5 Patented Nov. 11, 1930 PATENT OFFICE LOUIS JOSEPH JEAN BAPTISTE CHNEAU, OF PARIS, FRANCE TEMPERATURE-RESEONSIVE DEVICE Application led .Tun-e 27, 1927, 'Serial No. 201,933, and in Belgium July 3, 1926.

The present invention relates to tempera ture responsive devices and more particularly to those of the type adapted to be used in connection with re-alarm systems.

One of the objects of the invention is to provide a temperature responsive device which is not responsive to slow temperature changes but which will respond quickly to a rapid change in temperature.

Other objects will appear in the course of the following description of preferred embodiments of the invention shown in the accompanying drawings in which Fig. 1 is a diagrammatic section through one form of the device;

Fig. 2 is a diagrammatic longitudinal section through a second form of the device;

Fig. 3 is a section taken on line 8 8 of Fig. 2;

Fig. 4 is a longitudinal section of a third form of the device, and

Fig. 5 an end view of the embodiment of the invention shown in Fig. 4.

The embodiment'of the invention shown in Fig. 1 comprises a pair of concentric tubes 1 and 2 closed at their extremities by end closures 3 and 4 common to both tubes. Tube 2 is made of a thin material which is a good conductor of heat, while tube 1 is formed of material which is a poorer conductor of heat than the material of tube 2. An orifice 5 is formed in the wall of tube l adjacent the end closure 4 and a diaphragm 6 of corrugated metal (preferably nickel plated copper) extends transversely of the tube 1 adj acent said orifice 5, thus forming a pair of isolated chambers 7, 7 within the tube 1. A screw 8 mounted in but insulatedL from end closure 4, extends longitudinally of the chamber 7 and contacts with diaphragm 6 when the latter is in its position of "rest.

The screw 8 also serves as one terminal of an electric circuit, and a second terminal 16 is mounted on closure 3. The apparatus operates as follows: Assuming the device to be properly connected in circuit with an electric or luminous or sound signal system and that the temperature surrounding the device is slowly rising, heat will pass through wall 2 and raise the temperature of the air or other Huid contained in the space between tubes 1 and 2; butv since tube 1 is capable of conducting heat, the temperature of the fluid in chamber 7 will also rise and diaphragm 6 will remain at rest. If on the contrary, the temperature surrounding the `device rises suddenly, the fluid in chamber 7 will be more quickly heated than that in chamber 7 and the resulting difference in pressure will cause diaphragm 6 to flex away from the end of the screw 8 and interrupt the flow of current between terminals 16 and 8. This interruption of current iow may be utilized as in French Patents No. 327,152 and No'. 320,702, to close a circuit connected to the fire alarm. It will be noted that the device is so constructed that, when the temperature within the chamber 7 becomes approximately the same as lthat within the chambery 7, diaphragm 6 will flex back into contact' with the end of the screw 8. vIn other words, after the device has been heated for a certain length of time or, if it be permitted to cool, all the working parts will be restored to the position of rest7 and the fire-alarm signal will cease automatically.

In the embodiments of the invention shown in Figs. 2 and 3, the tube 2 of Fig. 1 is' replaced by a series of tubes 2 which, like the tube 2, are good conductors: off heat, thetube 1 being here again a poorer conductor of heat. A closure 8 seals tube 1 and tubes 2 at one' end. The other ends of tubesy 2l open into a chamber 7 formed by an end closure 4 and a wall 9 closing the corresponding end of tube 1. An open-ended cylinder 6C has one of its ends connected to a circular orifice in wall 9 and a' piston 62 worlrs in said cylinder with a minimum of friction. Piston 62 is normally held by a compression spring 6 in contact with the end of a screw 8 mounted in but insulated from the closure 4. Current is supplied to the device by means of leads connected to screw 8 and to av termi-nal 16 mounted on closure 8. This embodiment of the invention operates in a manner similar to the one shown in Fig. 1. The piston 62, which replaces the diaphragm 6 of Fig. 1, is subject to the differences between the pressures existing in the chambers 7 and 7 and operates to break the circuit between the terminals 8 and 16 upon a rapid rise of temperature.

The embodiment of the invention shown in Figs. 4 and 5 comprises an inner tube 1 and an annular chamber 2 surrounding the tube 1 and closed at both of its ends, the tubes forming the chamber 2 having the same relative heat conducting properties as the tubes 1 and 2 in Fig. 1 and the tubes 1 and 2 in Fig. 3. One end of tube 1 is sealed by closure 3 and the vother end by wall 9 and a group of elements 60, 62, 6 similar, respectively, to the elements 6, 6 and 62 illustrated Y* in Fig. 2. Theluid in chamber 2 is Jfree to Apass from said chamber through one or more conduits to act on piston 62 which forms the movable wall separating the chambers 7 and 7. The rigid portions of chamber 7 consist of a cylindrical member 11, insulating disc 4, a plug 12 of conductive material threadedly engaging with disc 4 and held in place. by a nut 12, and a screw 8 mounted in a bore of the plug 12 and having its end normally contacting with the piston 62. Current is led to screw 8, through plug 12 from a cap 13, threadedly engaging with the latter, said cap being in contact with a longitudinally adjustable binding post 8 carried by a bar 14 which extends diametrically of one end of a perforated cylinder 15 surrounding but spaced Jfrom the outermost of the tubes which form the chamber 2. Oneend of the tube 1 is supported within and spaced from the innermost tube which forms the chamber 2 by the binding post 8', cap 13, disc 4, and member 11. The other end ofthe tubevl is Asupported by strips 10 which bridge the space between the tube l and the innermost tube of the chamber 2. This embodiment of the device functions in substantially the same manner as the one represented in Fig. 2, the special end structure being designed to prevent Vtampering With or derangement of the setting screw 8.

Each of the devices shown-in Figs. 1, 2 and 3, and 4 and 5 may beconstructed as above described or each may be provided,

Y either with a very small orifice such as that Y shown at 2O in Fig. 2, by means of which the two chambers 7 and 7 communicate one with another and which assures the equilibrium under all conditions except when very Vabrupt temperature changes take place, or with 1 very small orifices, such as those shown at 21 and 22 in Fig. 4, said orifices allowing the Huid in each chamber to escapeslowly to the atmosphere as the temperature slowly rises, thus renderingthe device sensible only tov very abrupt changes of temperature. Y

v IIhe invention is not to be taken as limited .to the particular constructions hereinbefore second chamber having a wall formed of a n relatively good conductor of heat, a pressure responsive partition forming at least part of a common wall separating said chambers from one another, electrical contacting means associated withsaid partition,"and an electrical terminal in conductive relation with one of the walls of one of said chambers..

v 2. A device of theclassdescribed comprising in combination a central'chamber, a second chamber external to and concentric with, said central chamber, a pressure responsive partition separating said chambers,rand electrical contacting means positioned adjacent said partition and adapted to contact there- 

